Quality Differentiation and Mechanistic Insights Into Green Tea Processed by Different Fixation Methods

Area of Science:

• Food Science
• Agricultural Chemistry
• Sensory Science

Background:

• Green tea quality is influenced by processing, particularly the fixation stage.
• Understanding how different fixation methods impact chemical composition and sensory attributes is crucial for quality control.

Purpose of the Study:

• To systematically investigate the effects of three distinct green tea fixation methods—roller fixation (CQ), mixed fixation (HC), and steam fixation (ZQ)—on the formation of tea quality.
• To correlate chemical profiles with sensory characteristics to guide processing decisions.

Main Methods:

• Quantitative analysis of aroma compounds, catechins, free amino acids, and alkaloids.
• Electronic tongue taste fingerprinting and untargeted metabolomics.
• Molecular docking to assess metabolite-receptor interactions.

Main Results:

• Fixation methods significantly altered volatile and non-volatile metabolite profiles.
• CQ enhanced polyphenols and gallic acid, leading to bitter/astringent taste.
• ZQ produced the brightest green infusion and highest sweetness; HC balanced aroma compounds and amino acids.

Conclusions:

• Fixation methods impact green tea quality by regulating metabolic pathways like phenylpropanoid biosynthesis and caffeine metabolism.
• Differential binding affinities of metabolites to taste receptors explain taste variations.
• Provides a framework for precision green tea manufacturing based on desired sensory profiles.